precious little reading. He certainly got suckered by Stalin in the 30's, but many Americans got suckered too, and not only lefties. He was a brilliant writer, and conversationalist who wanted (at least intellectually) a floor under the social system, but was really politically a dilletante. One of what were called the Fabian Socialists, like H.G. Wells, the Webbs et al. He believed in the fads of progressive thinkers at the end of the 19th Century, free love, social legislation, eugenics, as did many Americans at the time, viz. Margaret Sanger and dozens more who made far more of an impression on American societal development than hard right thinkers of the time. Can you name one without looking it up?
By the way, Health Care was proposed and pushed through Parliament in Britain in 1909 by none other than that raving Socialist Winston Churchill.
But the statement was a joke, which you might have seen if you troubled to look. He also said "He who can does, he who cannot teaches." That too is a joke, because to teach something, you need to know it better than your average person in order to make others understand and to answer questions.
Now I don't hold his opinions up as shining examples of truth, but as very funny statements because they are very funny.
Most of them are appended to the play Man and Superman, in something called the Revolutionists Handbook and Pocket Companion. Should you read it you would see at once how naive were his politics, and how funny were his aphorisms. They're very like Ambrose Bierce's in The Devil's Dictionary, which given my fuzzy memory may actually be the origin of the definition of marriage I quoted.
Eugenics and selective breeding to raise the quality of the populace was a very popular idea in the late 19th and early 20th Centuries, and the US was one of the places it took hold quite virulently. People still believe that the wealthy are somehow superior to the rest of us, and that their accumulation of wealth is some sort of an indication of that superiority. That's certainly not an opinion I agree with, just look at the Kennedys.